JPH0358038A - Multipule-dimming camera - Google Patents

Abstract

PURPOSE:To attain exposure well balanced with a background by deciding flash light emitting quantity from each photometric value predicted by operating the focal position information of each area at the time of releasing. CONSTITUTION:When charges are accumulated in line sensors LS1 - 3 by CLSH signals until their maximum quantity reaches a prescribed quantity, FB signals are outputted from focal point detecting units 61 - 63 and the accumulated charges are sample-held. As for a microcomputer MCI, phi signals are outputted in response to FB signals from the units 61 -63, the accumulated charges are sent as DLS signals to the MCI, the prescribed operation is carried out, and a focal point adjusting motor is driven by a lens control circuit. When AF operations are completed, the MCI sends information on a zone in the deapth of the object and a well focused zone to a storoboscope flashing and dimming control circuit 5, and the control circuit 51 sends TTLG signals to dimming circuits 52 - 54. When a X contact point 10 is turned on, the circuit 51 controls a stroboscope 55 so that light emission is carried out in response to a STA signal, dimming is started by TTLR signals, and the light emission is stopped by a STP signal in response to CMP signals outputted from the circuits 52 - 54 when the dimming is completed. Thus, appropriate exposure can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention measures the reflected light of light projected toward a subject from a flash emitting unit in a plurality of areas, and adjusts the flash light emission according to these photometric values. This invention relates to a multi-flash control camera that determines the amount of light emitted by each section.

(Background of the Invention) Conventionally, a flash light emitting unit is emitted toward a subject, and the reflected light from the subject is measured to determine the intensity (light amount) of the reflected light.
There are many cameras on the market that have a dimming type that determines the amount of light emitted depending on the amount of light emitted.

However, most of them use a single photometric sensor to measure the light in the center of the screen and adjust the light, so if the main subject is located in the center of the screen and is of an appropriate size, it is suitable for shooting. However, if the main subject is not located in the center of the screen or is small in relation to the screen, the problem is that the appropriate exposure cannot be obtained due to the influence of the background light. was there.

In view of this, JP-A-60-108827 proposes a multi-flash control camera in which a plurality of photometric sensors are arranged and each is variably controlled to determine (control) the amount of light emitted. The photographer must use an external operation to determine which area to focus on when metering, and this operation is cumbersome.

Furthermore, in JP-A No. 55-135823, by measuring the light of multiple areas of the screen when there is no flash and when there is a flash, and comparing these light measurement values, it is possible to take pictures of the subject closest to the camera. An area with an image was selected, and the amount of light emitted was controlled by the photometric value of that area. With this method, the exposure will be appropriate for the closest object, but if the main subject is not the closest, the exposure will not be appropriate for the main subject, and the balance with the background will also be considered. It wasn't.

Furthermore, in US Pat. No. 4,796,043, etc., a method has been proposed in which multiple areas of the screen are individually photometered and exposure is performed based on the photometric value of the area corresponding to the distance measurement area. There is no mention of photometric evaluation of Photometric evaluation of a subject illuminated by a flashlight differs greatly depending on the distance of the subject from the flashlight, the duration of the flashlight, etc., and is different from the photometry of steady light. Furthermore, with recent cameras, distance measurement is performed repeatedly.
Some cameras have an AF mode (hereinafter referred to as predictive servo mode) that predicts the movement of the subject so that it will be in focus at the time of release based on current and past distance measurement information, but when using this mode, the exposure of the main subject during flash photography No method has yet been proposed that takes into account control and the balance between the main subject and the background. (Objective of the Invention) An object of the present invention is to solve the above-mentioned problems, and to ensure that the main subject is properly exposed and that it matches the background without any troublesome operations, no matter how the subject moves within the screen. The objective is to provide a multi-flash control camera that can take well-balanced photographs. (Features of the Invention) In order to achieve the above object, the present invention calculates and predicts the focus information of each area at the time of release from the information from the distance measuring means, and based on this focus information, each area from the photometering means. It is characterized by providing a light control means for evaluating the photometric value and determining the amount of flash light emission, and thereby controlling the amount of flash light emission based on each predicted focal point information corresponding to each photometry area. do.

(Example of the invention) FIG. 1 is a block diagram showing one embodiment of the present invention.

In the nuclear diagram, 1 is a microcomputer that controls the movement of each part of the camera, and 2 is a lens control circuit that drives and controls the focusing mechanism of the photographing lens (not shown) and the aperture blade control motor. While the control circuit 2 is receiving the LCOM signal from the microcomputer 1, it performs serial communication via the data bus DB[lS, and when it receives motor drive information through the serial communication, it drives the aforementioned motor (not shown) using that information. Control. At the same time, the lens control circuit 2 sends various information about the lens to the microcomputer 1 through serial communication. Reference numeral 3 denotes a liquid crystal display circuit for driving a liquid crystal display (not shown) for informing the photographer of various shooting information of the camera, such as shutter speed and aperture value, and receives a DPCOM signal from the microcomputer 1. During this time, serial communication is performed via the data path DBUS, and when display data is received via serial communication, the liquid crystal display is driven according to the display data. Reference numeral 4 denotes a switch sense circuit which reads the status of switches used by the photographer to set various photographing conditions and switches indicating the status of the camera and sends it to the microcomputer 1.
While receiving the SWCOM signal, the data of the various switches is sent to the microcomputer 1 through serial communication via the data path DBUS. 5 is strobe light emission and TTL! This is a strobe light emission dimming control circuit that controls the light emission stop function using II light.
While receiving the OM signal, it performs serial communication with the microcomputer 1 via the data path DBIJS, and performs various controls by receiving data related to strobe control. Reference numeral 6 denotes a focus detection circuit which is a unit consisting of a line sensor for performing AF using the existing phase difference detection method and a circuit for accumulating and reading out the line sensor, and is controlled by the microcomputer 1.

Reference numeral 7 denotes a photometry circuit that performs photometry of the subject under the control of the microcomputer 1, and the photometry output obtained here is sent to the microcomputer 1, where it is A/D converted and used to set exposure conditions. .

Reference numeral 8 denotes a shutter control circuit that controls the movement of the leading and trailing shutter curtains (not shown) according to control signals from the microcomputer 1. A feeding circuit 9 controls a feeding motor (not shown) according to control signals from the microcomputer 1, and winds and rewinds the film. Reference numeral 10 denotes an X contact which has the role of informing the strobe light emission control circuit 5 of ONL and the strobe light emission timing at the timing when the front curtain of the shutter completes its travel.

SWI is a switch different from the release button of the camera, and when the microcomputer 1 recognizes that the switch SWI is ONL, the microcomputer 1 starts the exposure operation.

FIG. 2 is a block diagram showing an example of the structure of the strobe light emission control circuit 5. As shown in FIG.

In the figure, 51 is a control circuit that exchanges data with the microcomputer 1 through serial communication and controls the dimming circuits 52, 53, 54 and the strobe light 55.

The dimming circuits 52 to 54 each include a logarithmic compression amplifier, an expansion transistor, an integral capacitor, etc., and are TTL
Light control is started by the R signal, photoelectrically converted by a photodiode (hereinafter referred to as light control sensor) PD, and the image plane light amount of the input film surface is amplified by a logarithmic compression amplifier, and TTL
A gain is applied by the expansion transistor according to the value of the G signal (gain information for dimming), and the signal is integrated by the integrating capacitor.

When the charge on the integral capacitor exceeds a predetermined value, a CMP signal is output to the control circuit 51. The strobe 55 is an existing one, and when sufficient charge for light emission is stored, the FVL signal notifies the control circuit 51 of completion of charging. When the STA signal is sent from the control circuit 51 that receives this, it starts emitting light, and then when the SPT signal is sent, it stops emitting light.

FIG. 3 shows the sensitivity area of the dimming sensor PD and the sensitivity area of a focus detection line sensor, which will be described later.

The light control sensor PDI~3 is arranged facing the film surface of the camera, and has a sensitive area with respect to the screen as shown in FIG. Also, focus detection line sensors LS1 to LS3, which will be described later,
has sensitivity areas as shown in FIG. 3 on the screen by an optical system (not shown), which correspond to the sensitivity areas of the dimming sensors PDI to 3, respectively.

FIG. 4 is a diagram showing an example of the configuration of the focus detection circuit 6 shown in FIG. It consists of

Next, the camera operation after the focus detection operation will be explained using the above-mentioned FIG. 4 and the like.

By the CLS}l signal from the microcomputer 1,
The line sensors LSI to LS3 each perform photoelectric conversion and start storage. When the maximum of the accumulated charges of the line sensors LS1 to LS3 reaches a predetermined value, the focus detection units 61 to 63 output an FB signal and stop accumulation, and sample and hold each accumulated charge. do. The microcomputer 1 controls all the focus detection units 61 to 61.
When it detects that the FB signal has returned from 63, it outputs a φ signal (clock signal) and the focus detection units 61 to 63
63 sequentially samples and holds the accumulated charges according to the φ signal and sends them to the microcomputer 1 by applying the DLS signal. The microcomputer 1 receiving the DLS signal A/D converts this signal, performs predetermined calculations, and performs serial communication with the lens control circuit 2 based on the calculation results. The lens control circuit 2 drives the focus adjustment motor based on the sent data. At this time, the line sensor L on the screen
Various proposals have been made regarding which area to focus on among the sensitivity areas of SI to LS3. For example, you can focus on the object closest to you, or you can focus so that all areas are within the depth of field.

When the microcomputer 1 finishes the AF operation as described above, it sends information to the strobe light emission control circuit 5 such as which zone is in focus and which zone is within the depth of field. Then, the control circuit 51 in the circuit S adjusts the light control circuits 51 to 5 based on the sent focus information.
Send dimming gain information (TTLG signal) to 3. After that, when the X contact 10 is turned on, the control circuit 51 starts the strobe 55 to emit light using the STA signal, and at the same time, the TTI,
Light control is started by the R signal. And the dimmer circuit 52~
When a CMP signal is sent from the strobe 54 to indicate completion of dimming, the strobe 55 stops emitting light using an STP signal.

Focus on each zone. FIG. 5 shows the relationship between the out-of-focus state and the dimming gain, and the relationship between the CMP signal and the STP signal.

The control method shown in FIG. 5 is just an example, and the setting of the dimming gain can be infinitely selected depending on each focusing condition such as "appropriate", "under a predetermined step", and "over a predetermined step". Also, the light emission stop control is rOR (logical sum).
In addition, rAND (logical product) J (which outputs the STP signal when all the signals from CMPI to 3 are received) can also be selected. Further, when the light adjustment correction is applied, the light control gain correction may be applied to both the in-focus zone and the non-focus zone, or the light control gain correction may be applied only to the in-focus zone.

FIGS. 6(a) to 6(C) are flowcharts showing an outline of a series of operations of the camera, and diagrams to help explain the operations.

Switch sensing is performed in step 1, photometry is performed in step 2, and display (photometry information, etc.) is performed in step 3. In the next step 4, a distance measuring operation is performed, and the process proceeds to step 5. In step 5, select the current AF mode and maintain focus. Determine the non-retention state and predictability state and return to step 4, or step 6
Otherwise, it is determined whether to proceed to step 7 (see FIG. 6(b)). In other words, when the focus is already maintained in AP one-shot mode (a mode in which the focus is maintained once the focus is achieved), the lens distance is IIi! The ring is not driven and the process immediately proceeds to step 7. If the focus is not yet maintained, the process proceeds to step 6, where the lens distance ring is driven to maintain the focus, and the process proceeds to step 7. In addition, when in AF prediction servo mode (a mode that predicts the movement of the subject so that it will be in focus at the time of release), if it is determined that the number of distance measurements is insufficient for prediction, return to step 4 and perform distance measurement. When it is determined that distance measurement has been repeated repeatedly enough to make a prediction, the process proceeds to step 6, where the lens distance ring is driven to maintain focus, and the process proceeds to step 7.

When the release button is not pressed, the sequence from step 1 to step 7 is repeated.

When the release button is pressed, the process advances from step 7 to step 8, and the following sequence is performed.

In step 8, distance measurement is performed, and in step 9, A
Determine F mode. As a result, if it is in the AF full shot mode, the process immediately proceeds to step 12 without driving the lens distance ring, and if it is in the AF predicted third mode, the process proceeds to step 10, and at the time of release (during exposure) The position of the subject is calculated and predicted based on the distance information up to that point, and in step 11, the lens distance ring is driven to the predicted focus position, and the process proceeds to step 12 (see FIG. 6(C)). In the next step 12, the dimming level is set.
In the AP one-shot mode, the dimming level is set based on the focus information (in-focus/out-of-focus information) of each area based on the latest distance measurement. In the AF prediction servo mode, the focus state (main subject position within the screen) of each area at the time of release (during exposure) is predicted based on the information obtained in step 10 above. When preparations for dimming control are completed, the process proceeds to step 13, where shutter control is performed, that is, the shutter is controlled to expose for a predetermined period of time. At that time, the strobe light is emitted and stopped. When the release is completed, one frame of film is fed in step 14 for the next photographing.

Here, a supplementary explanation will be given regarding the prediction method in the AP prediction servo mode.

First, by distance measurement before release, the focus state of each area is determined, and it is determined in which sensitivity area the main subject is located. By repeating distance measurement, focusing state determination, and main subject position determination before release, it is possible to predict in which sensitivity area of the photometric sensor the main subject will be located at the time of exposure after release is started (Step 10 in Figure 6). ). For example, suppose that the screen (photometering and distance measurement area) is divided into 12 areas (divided into areas from ■ to @) as shown in Figure 7, and the main subject such as a child or car is running. Consider the case where the subject is moving from left to right as shown in Figure 7 (A) and (B). Assume that the main subject, who was in area ■, was in area ■ just before the release. Then, it is predicted that exposure will occur when the camera moves to area (2) during the release time lag, and the light control gain is set with area (2) as the focus zone.

FIG. 8 is a block diagram showing a strobe light emission control circuit in another embodiment of the present invention, and the other circuits constituting the camera are the same as those in FIG. 1.

The control circuit 51, photometric sensors PD1 to PD3, light control circuits 52 to 54, and strobe 55 are almost the same as the strobe light emission dimming control circuit shown in FIG. 2 in the embodiment, but an addition circuit 56, The major difference is that a level detection circuit 57 is added.

The dimming circuits 52 to 54 do not output the CMP signal, but output the LVLI to 3 signals, which are the values integrated into the integrating capacitors. The adder circuit 56 logarithmically transforms the LV'L 1 to 3 signals and outputs an ADL signal which is the added value. When the ADL signal exceeds a predetermined value, the level detection circuit 57 detects the CMP signal.
Output the signal. The operations of the control circuit 51 are the same as those in the previous embodiment, including setting the dimming gain information (TTLG signal), starting the light emission of the smartphone/robot 55, starting the dimming operation, and CM.
It performs operations such as stopping the light emission of the strobe 55 in response to the input of the P signal.

The dimming gain is set so that the CMP signal is output when the desired amount of image plane light is reached in each zone.

Further, even if the amount of light on the image plane is the same, the balance of each zone changes by changing the weighting of the dimming gain in each zone. The situation will be explained with reference to FIG.

In the example of FIG. 9(a), the LV when each zone is properly exposed
The light control gain information (TTLG signal) is set so that the logarithmically converted value of the L signal becomes "3:1:l". When the zone of the weighted light control sensor PDI becomes one step over, and when the zones of the photometric sensors PD2 and PD3 each become -1.5 steps under, a CMP signal is output. In other words, zones that have been weighted will not be affected too much even if zones that are not weighted are too bright or too dark, and will be able to obtain an exposure close to the appropriate amount, and zones that have not been weighted will also be able to obtain an exposure that is close to the appropriate exposure. Since the exposure amount is not far off, a well-balanced exposure amount can be obtained for the entire screen.

The example of FIG. 9(b) is also the same.

In this other embodiment, the weighting of the dimming gain is changed depending on the in-focus/out-of-focus information of each zone. i.e. the focus zone,
According to this embodiment, by weighting the zone within the depth of field as shown in Figure 10, it is possible to take a well-balanced strobe photo with appropriate exposure for the main subject (the subject you want to focus on). For example, the position of the main subject at the time of one release is predicted from distance measurement information immediately before release and past distance measurement information, that is, the focus state of each area is predicted, and the focus information (in-focus/out-of-focus information) is calculated. Since the photometric value is evaluated based on the , and the amount of light emitted is controlled, the position and size of the main subject can be predicted to some extent, no matter how the main subject moves within the screen. It is possible to realize a multi-flash control camera that can perform control so that the main subject is exposed appropriately, and can also control the amount of flash light to provide an appropriate amount of exposure that is well-balanced with the background.

(Correspondence between the invention and the embodiments) In this embodiment, the focus detection circuit 6 is used as the distance measuring means of the present invention, and the light control circuits 52 to 54 and the photometric sensors PDI to PD3
is the photometric means, the control circuit 51 (FIG. 2), or the control circuit 51. Addition circuit 56. The level detection circuit 57 (FIG. 8) corresponds to the dimming control means. (Effects of the Invention) As explained above, according to the present invention, the focus information of each area at the time of release is calculated and predicted from the information from the distance measuring means, and each light metering from the photometry means is performed based on this focus information. A light adjustment control means is provided to evaluate the value and determine the amount of flash light emission, and the amount of flash light emission is controlled based on the predicted focus information corresponding to each photometry area. No matter how you move around inside the camera, you can take photos with the main subject properly exposed and well-balanced with the background without having to perform any troublesome operations.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing an example of the structure of the strobe light emission control circuit shown in FIG. 1, and FIG. A diagram showing the relationship between the sensitivity area and the sensitivity area of the focus detection line sensor, FIG. 4 is a block diagram showing an example of the configuration of the focus detection circuit shown in FIG. 1, and FIG. 5 shows the focus state in an embodiment of the present invention. FIG. 6 is a flowchart showing a series of operations in an embodiment of the present invention, and FIG. 7 is a diagram showing the relationship between dimming gain and light emission stop control.
8th diagram for explaining the operation in F prediction servo mode in detail
The figure is a block diagram showing an example of the structure of a strobe light emission control circuit in another embodiment of the present invention, and FIG. A diagram illustrating the changes, Figure 1○, is a diagram similarly showing the relationship between the focal state and the dimming gain in another embodiment of the present invention. 6... Focus detection circuit, 5... Strobe light emission control circuit, 51... Control circuit, 52~
54...Dimmer circuit, 56...Addition circuit, 57...Level detection circuit, PDI'-PD3
・・・・・・Photometric sensor. Figure 2 (Strobe full light control circuit) Figure 3 Figure 4 (Focus output 0 path) Figure 7 (A) (C) 8

Claims (1)

[Claims] (1) A multi-flash control camera equipped with a photometer that measures the reflected light of a flash of light projected toward a subject in each of a plurality of areas, and a distance measurement unit that repeatedly measures the distance of each of the plurality of areas, A dimming control means that calculates and predicts focus information for each area at the time of release from the information from the distance measuring means, evaluates each photometric value from the photometry means based on the focus information, and determines the amount of flash light emission. A multi-flash control camera characterized by the following: